1. Field of the Invention
The invention relates to a transfer assist apparatus, for example, a transfer assist apparatus that assists in a transfer operation for a person who cannot walk by oneself to transfer from a bed to a wheelchair or from the wheelchair to the toilet seat.
2. Description of the Related Art
For a care-receiver who cannot walk by oneself, it is not easy to perform by oneself the transfer movement of moving from a bed to a wheelchair. Usually, a nursing assistant has to help, but the aid in transfer movement places a large physical load on the nursing assistant and a large mental load on the care-receiver. Apparatuses that assist the transfer movement of a care-receiver who cannot walk by oneself have recently been developed. For example, Japanese Patent Application Publication No. 2006-305092 (JP-A-2006-305092) discloses a transfer assist apparatus in which a tiltable strut is provided in a raised condition on a rotatable platform and a receiving plate (holding device) is provided at the distal end of the strut. When the care-receiver has a transfer movement by using such a transfer assist apparatus, the strut is tilted and the receiving plate is brought close to the care-receiver's body. Then, the care-receiver sets hands on the holding device, clutches the holding device, moves the body onto the receiving plate, and places the body weight thereon. Where the strut is then lifted, the care-receiver's body is also lifted. After the transfer destination is reached, the strut is tilted to complete the transfer movement.
It is obviously an important problem to ensure safety of the care-receiver during the transfer assist. Japanese Patent Application Publication No. 8-191865 (JP-A-8-191865) and Japanese Patent Application Publication No. 7-016269 (JP-A-7-016269) disclose safety mechanisms in electric nursing lifts. Thus, JP-A-8-191865 discloses an electric nursing lift that hoists the care-receiver from a bed or lowers the care-receiver onto the bed, the lift having a structure such that the hoisting arm can be stretched and contracted. Therefore, even when the electric nursing lift is erroneously controlled and the care-receiver is inserted between the hoisting means and the floor, the hoisting arm is contracted to absorb the force acting upon the care-receiver. As a result, the care-receiver's safety is reliably guaranteed.
JP-A-7-016269 discloses providing a bed with an aid arm that prevents tumbling and using a structure such that restricts the movement of the hoisting arm so as to allow the hoisting arm to rotate only when the aid arm protrudes to the outside of the bed. As a result, the bed is prevented from accidents such as overturning, and care-receiver's safety is protected.
A care-receiver that requires a transfer assist has disabled zones on the body, for example, a paralyzed half of the body or paralyzed legs and cognitive impairment. Therefore, significant sense of anxiety and fear are obviously associated with a transfer movement. Furthermore, during the transfer movement, the care-receiver with a disabled body has to entrust the entire own body to a nursing assistant or a nursing robot. The nursing assistant performs the aid and transfer assist, while listening to the care-receiver's wishes, and the care-receiver's sense of anxiety and fear can be mitigated based on the trust relationship between the nursing assistant and the care-receiver. However, when the transfer assist apparatus is used, the care-receiver can hardly trust the apparatus to the same extent as the nursing assistant and the sense of anxiety and fear grow additionally. One more problem associated with the transfer assist apparatus is the presence of various factors causing sense of anxiety and fear in the care-receiver, such as operation noise caused by a motor and gears, unpredictable abrupt acceleration, transfer trajectory undesirable for the care-receiver, and operation failures. Therefore, a transfer assist apparatus that can ensure not only the care-receiver's safety, but also guarantee a sense of relief is highly desirable.